net/core: Add reading VF statistics through the PF netdevice

Add ndo_get_vf_stats where the PF retrieves and fills the VFs traffic
statistics. We encode the VF stats in a nested manner to allow for
future extensions.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6f5f71f..e20979d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1100,6 +1100,10 @@
 						     struct ifla_vf_info *ivf);
 	int			(*ndo_set_vf_link_state)(struct net_device *dev,
 							 int vf, int link_state);
+	int			(*ndo_get_vf_stats)(struct net_device *dev,
+						    int vf,
+						    struct ifla_vf_stats
+						    *vf_stats);
 	int			(*ndo_set_vf_port)(struct net_device *dev,
 						   int vf,
 						   struct nlattr *port[]);